Formation processes of weathering products of pumice collected from a rhyolitic pyroclastic flow deposit were investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDX). SEM clearly showed the presence of some weathering products adhering to the surface of pumice. XRD showed that the products were composed mainly of noncrystalline materials with a relatively small amount of halloysite (10 Å). TEM and EDX revealed texture transformation sequences from the earliest weathering product to a final product of halloysite as follows: 1) precipitation of very thin flaky or film-like noncrystalline Al-hydroxide; 2) transformation into irregularly aggregated Al-Fe-Si-rich fibrous material; 3) morphological changes to rounded aggregates; 4) development of halloysite-like curled domains with successive decrease in Fe content; and 5) further development of curled domains in rounded aggregates. These materials must be metastable phases at early reaction stages with kinetics limiting formation of the stable equilibrium phase of kaolinite.

What relationship is there between violence and language?* What happens when language is the main target of attack? We should perhaps begin by defining the inner logic of violence, and then tackle the question of the monstrous hybrid it has created with language. In one of the texts that make up the collection entitled Difficile Liberte’, Lévinas remarks that violent action is an ‘action where one acts as if one were the only actor: as if the rest of the universe existed only to receive the action; thus every action is violent that we suffer without wholeheartedly collaborating in it’. So violence has two characteristics. On the one hand, it is fed by a fundamental illusion, that is, a fiction of the will that imagines it is so super-powerful and autonomous that it thinks that by itself it can decide the fate of ‘the rest of the universe’. On the other hand, it is never an authentic action, because it prevents others from owning it and becoming co-actors themselves. Thinking perhaps of Spinoza, Lévinas suggests that violence comes into being from the moment when individuals decide to stop being part of the ordinary world of actions and think, ‘like an empire within an empire’, they are the unique cause of their acts and gestures. This subjective decision is clearly a control decision that contradicts the requirement of common sense, which is to be understood here as a sense of the community. It leads inexorably to consigning others to the world of effects in order more easily to turn them into eternal victims. In Dostoevsky's The Idiot, Prince Mishkin perfectly embodies the figure of the other who continually ‘receives’ the action. But when interplay between the will and its own mirrors becomes excessive, individuals always end up confusing the reality of the world with the exaggerated trust they put in their own prejudices. Since the analyses of the psychiatrist Minkowski at least, we know quite well that the more the certainty naturally accompanying the prejudice increases and expands until it borders on madness, the more violence is likely to grow.

Cation exchange experiments were carried out on phlogopite, biotite, and muscovite using cryptand [222] as a complexing agent, dioxane as solvent, and Li as the exchanging cation. The results indicate greater than 90% exchange of the analyzed cations K+, Rb+, and Sr++ in phlogopite and biotite after two days. Similar results for the exchange in muscovite are observed but it is apparently slower. The amount of exchange observed for mica depends mainly on pH, time and the exchanging cation at a constant temperature. Residues of the mineral phase were also investigated by X-ray diffraction and a significant change of the interlayer spacing was detected. Some samples of the residue were analyzed for Li content. The compositions of the treated samples were in good agreement with the determined exchange of K+.

Jordanian natural kaolin and bentonite show good catalytic activity towards debutylating 2-tert-butylphenol, and varying debutylation vs. isomerization selectivity after acid activation. The resulting catalytic activity of these samples is dependent on the acid employed for activation; the samples treated with acetic acid showed relatively low conversions, whereas those treated with hydrochloric or phosphoric acid were found to be very active. Treatments with strong acids such as HCl have various effects on the activity of the samples depending on the concentration of the acid. For example, treatment with 1 M HCl gives the highest activity, whereas a treatment using 12 M HCl produced the lowest activity. The debutylation selectivity of the acid-activated samples is affected by the acid type and/or concentration. This selectivity ranges from 20 to 60%, whereas that of water-treated samples is between 46–82%.

Water retention curves of colloidal allophane and imogolite with different charges and different pretreatments were measured using a tension plate and a pressure plate apparatus. An irreversible effect of air-drying was found for the water retention of colloidal allophane even for particles of less than 50 nm in Stokes’ diameter collected from air-dried soil. This was attributed to the irreversible submicroscopic aggregation of allophane. Fresh allophane colloids with a low absolute net charge retained more water above −100 J Kg−1 than did highly charged ones due to the formation of a microporous structure. Allophane did not swell under ordinary conditions, but the relatively highly charged allophane recovered water retention above −100 J kg−1 during the wetting process. Imogolite retained 1.5 times more water than Na-montmorillonite at about −650 J kg−1 due to micropores formed by intertwining fibrous particles.

Redox cycles are common in nature and likely have a profound effect on the behavior of soils and sediments. This study examined a key component of redox cycles in smectites, namely, the reoxidation process, which has received little attention compared to the reduction process. Unaltered (oxidized) and reoxidized ferruginous smectites (nontronites) were compared using infrared and Mössbauer spectroscopies, and thermal gravimetric analysis. The infrared and thermal gravimetric data revealed that the structural OH content of reduced-reoxidized clay is about 15 to 20% less than in the original (oxidized) sample, indicating that the structure remains partially dehydroxylated even after reoxidation. Mössbaner spectra of reoxidized samples consisted of larger quadrupole splitting for Fe(III) doublets than in the unaltered samples, suggesting that the environment of Fe(III) is more distorted after the reduction-reoxidation treatment.

The three-dimensional crystal structure of rotationally disordered illite/smectite (I/S) in K-bentonite samples from the Appalachian basin and neighboring areas is described using the parameters of 1) P0, the proportion of zero-degree layer stacking rotations, such as in the polytype series 1Md-1M; 2) Pcv, the proportion of 2:1 layers with cis-vacant (cv) octahedral sites that are randomly interstratified with trans-vacant (tv) layers; and 3) P60 the proportion of layers with n·60° rotations (as opposed to n·120°) in the rotated layers. These parameters were determined by computer modeling of experimental randomly oriented powder X-ray diffraction patterns.

The proportion of cv interstratification in the I/S increases with A1 and decreases with Mg and Fe content. The proportion of n·60° rotations in the rotated layers increases with Mg and Fe content. The cv 120° disordered structure correlates with tetrahedral A1 for Si substitution and increasing tetrahedral charge. The tv n·60° disordered structures correlate with octahedral Mg for A1 substitution. The data indicate that the type of unit cell and nature of rotational disorder in I/S is controlled by the octahedral Mg content. The three-dimensional structures do not show any systematic correlation with Reichweite and percent expandability as determined from diffraction patterns of oriented sample preparations.

Chinese culture is distinguished among the world's other great traditions by the depth and intensity of its love for rock and stone. This enduring passion manifests itself both in the art of garden making, where rocks form the frame and the central focus of the classical Chinese garden, and also on a smaller scale, in the practice of collecting stones to be displayed on trays or on scholars’ desks indoors. This essay sketches a brief history of lithophilia in China, then adduces the most important philosophical presuppositions for it, and concludes by suggesting some implications for our experience of, and interactions with, the realm of stone and rock.

Lechuguilla Cave is a hypogene cave formed by oxidation of ascending hydrogen sulfide from the Delaware Basin. A unique sediment deposit with characteristics suggesting derivation from the land surface, some 285 m above, was investigated. At this location, the observed stratigraphy (oldest to youngest) was: bedrock floor (limestone), cave clouds (secondary calcite), calcite-cemented silstone, finely laminated clay, and calcite rafts. Grain-size analysis indicates that the laminated clay deposits are composed of 59-82% clay-size minerals. The major minerals of the clay were determined by X-ray diffraction analysis and consist of interstratified illite-smectite, kaolinite, illite, goethite, and quartz. Scanning electron microscopy observations show that most of the clay deposit is composed of densely packed irregularshaped clay-size flakes. One sample from the top of the deposit was detrital, containing well-rounded, silt-size particles.

Surface soils are probably the source of the clay minerals. The small amount of sand- and silt-size particles suggests that detrital particles were transported in suspension. The lack of endellite and alunite is evidence that the clays were emplaced after the sulfuric-acid dissolution stage of cave formation. Fossil evidence also suggests a previously existing link to the surface.

This issue of Diogenes includes short papers by prominent officers of 18 of the member-associations of the International Federation for Modern Languages and Literatures (Fédération Internationale des Langues et Littératures Modernes - FILLM) with a view to introducing and explaining the history, purpose, and function of these international learned societies representing different branches of the modern languages field at a time when the role of such bodies is often questioned even by professional academics working within the discipline, and their very existence largely unknown outside it, even to educated persons. The FILLM is one of the earliest member organizations of the International Council for Philosophy and Humanistic Studies (CIPSH) which had indeed had a prior existence since its foundation in Oslo in 1928 as the Commission Internationale d'Histoire Littéraire Moderne and was subsequently reorganized in its present structure in 1951 following the formation of UNESCO.

Since the time of the Renaissance, it has been believed in the West that Greco-Roman Civilization developed solely between Athens, Rome and Paris. In so doing, we forget the detour that Greek culture took into Muslim culture over a period of several centuries, and the influence of this culture on Muslim philosophy and science. This assumption also fails to take note of Muslim influence on Europe, in which Andalusia and Sicily acted as intermediaries. In order accurately to trace the spread of knowledge from Greece we must follow a path leading from Athens to Baghdad and Cordoba before reaching Paris. If we omit this historical reality, we underestimate the role played by Eastern Christians and Jews in the transmission of Greek knowledge to Islam, and from Islam to the West.

The red snow algae species found in snow at Resolute, Canadian Arctic, is a unicellular Chlamydomonas nivalis. Investigations by SEM-EDX, TEM, FT-IR, GC and GC-MS suggest that clay aerosols may provide nutrients for these unique systems. The clays provide P, S, K, Si, Ca, and Mg. Soot is also present and halite is very common. This salt probably plays a significant role in lowering the freezing temperature. The red snow algae is coated by a sticky thin film composed of both organic membrane material and inorganics consisting of mica and smectite. Green algae rich in Ca are involved in active photosynthesis while red algae are in a resting stage. Protamine, stearic acid, and decanoic acid were found at Ca-rich green cells while carminic acid and nopalcol BR-13 were found at Ca-poor red cells. The cell wall of red algae is composed of protein with cellulose. The major fatty acides in cells are all of even-carbon species with maximum concentrations of palmitic acid, stearic acid, and behenic acid, suggesting normal chemistry of algae species without C22. High concentration of n-alkanes with n-C24 is a characteristic component in this red snow algae, suggesting the presence of hydrocarbons that could be derived from the Arctic cold desert and/or organic debris of wind-transported bacteria. It is likely that such organic and inorganic matter provide the nutrient sources for the red snow algae in ice.

Diffusion of alkali and low-atomic-number elements during the microbeam analysis of some silicates by analytical electron microscopy (AEM) has been known for some time. Our repeated analyses at 300 kV of kaolinite, halloysite, smectite, biotite, muscovite and pyrophyllite, however, showed differential loss (relative to Si) of not only alkali elements (such as K, Na, Mg) and low-atomic-number elements (such as Al) but also higher-atomic-number elements (such as Fe, Ti). For AEM of these phyllosilicates, a Philips EM430/EDAX facility with a tungsten filament was used to provide a current of 0.3 nA in a stationary beam of nominal diameter 90 nm. The loss of Al in kaolin minerals during analysis is particularly severe. Kaolin crystals can be damaged by the electron irradiation over several seconds, making it the most sensitive clay to the electron beam; in general, relative phyllosilicate stabilities are kaolin < smectite < pyrophyllite < mica. A clear dependence of element loss on crystallographic orientation has been observed for layer silicates in our study; a greater element loss occurred when the plane of the specimen foil was perpendicular to the basal planes of the phyllosilicate crystals than when the foil was parallel to the basal planes. Lower beam current, larger beam diameter and thicker specimens all reduce the loss of elements. The initial stage of irradiation produces highest rates of element loss and the rate of loss can be fitted by an exponential decay law. The analyses at low temperature of phyllosilicates showed that element loss remains serious in our analytical conditions. Since the element loss appears to be instrument- and method-dependent, one should use closely related, well-characterized phyllosilicates as compositional standards to calibrate any AEM instrument that is to be used to analyze unknown phyllosilicates, and the standards and unknowns should be analyzed under identical conditions.

To mention what is called the “Silk Routes” today is to evoke more than two thousand years of history on two continents, Europe and Asia. Naturally, over such a long period and such vast territories, hundreds of products were transported, exchanged, stolen, conquered, transferred, in short, from one country to another. For some of these products, the very source of the raw materials and the techniques of production themselves were transferred.

Everyone knows that the Chinese invented paper, printing, gunpowder and the compass—great technological advances; as for the last three, their transmission throughout the world goes back only to the Crusades, which is quite recent. Here we are interested in transfers that are less known and more ancient, the most ancient for which precise records exist, starting from the time of the “opening” of the silk routes, which, according to Chinese classical history, was during the second century B.C. We shall stop around the eleventh century A.D., at the time of the Sung dynasty. This period includes the two most interesting epochs, in our opinion, in the history of the exchanges on these routes: the Han dynasty (from 206 B.C. to 220 A.D.) and the Tang dynasty (618-907), epochs whose time frames encompass the Western Roman empire, the Eastern Roman empire, the kou-chau empire, Sassanid Persia, and the first centuries of Islam.

When the “object” gazed at is called Africa and when the gazing subject is Africa, the observer cannot help but conclude that any gaze that is related to Africa is an intersection of gazes calling forth several questions: Who is looking at Africa? What is Africa looking at? Who looks at the one who is looking at Africa? Two problems emerge from this: the identification of the subject, and the discrimination among objects and themes produced by the limited scope of these gazes. If the gaze at (or of) Africa is an intersection of perspectives, these perspectives will only find stability if they are related to the African history that is in the making. This is a plural history, for geographic diversity, and the multiplicity of acting figures and sociopolitical organizations give African history a “changeable and diverse” character. Any evaluation of the relationship of Africans to their history must be an attempt, a sketch that makes no pretense of providing a unique and certain interpretation of the African lived experience (Erlebnis) by implementing the kind of controlling philosophy of history that fixes the beginning, the length, and the order of a people's history. It is more a question of restating, with the uncertainty that characterizes any evaluation of a specific history, the problem of the relationship of African history to its becomings. How, by which conditions and through which actors does this plural history speak its moments of creation today? At its heart, how does it articulate the conflicting overlap of the gravity of existing institutions and the audacity of creation? The exploration of these questions first centers around the often discussed theme of African identity (self). The stakes at this level involve the detachment of the conditions of a dynamic re-appropriation from this notion of identity - at the very moment when globalization is conjugating itself by turns in the imperative, the indicative, and the conditional. Next, the examination will focus on relationships to otherness (the other). How can intersubjective relations be declined differently?

Sedimentary zeolites clinoptilolite, mordenite and erionite occur as diagenetic products of ash falls of rhyolitic composition from the Oligocene Chichindaro Formation at the limits of the Mexican Volcanic Belt with the Mexican Highland. These zeolitic tuffs were formed from open hydrologic environments where rhyolitic glass altered to clinoptilolite + opal-C and to clinoptilolite + mordenite + erionite + opal-C. The process of diagenesis was hydrolysis associated with the removal of SiO2, K2O, and Na2O from the rhyolitic precursor and enrichment of Al2O3, MgO, and CaO. The crystallization of clinoptilolite occurs at ratios of SiO2/Al2O3 between 4.91 and 7.14 and (K2O + Na2O)/(MgO + CaO) from 2.19 to 0.79. Formation of clinoptilolite appears to be directly from glass and through a vitreous proto-zeolite intermediate. The zeolitic tuff is in contact with a vitric tuff where ash falls were devitrified to K-feldspar and diagenetically altered to smectite + opal-C.